Thermal Reaction Norms of Locomotor Performance in Lacertid Lizards of the Genus Takydromus

Abstract

Thermal reaction norms of sprint speed were examined in three lacertid lizard species (Takydromus tachydromoides, T. smaragdinus, and T. dorsalis). We found inter- and intraspecific variations in maximum sprint speed, optimal body temperature, and thermal performance breadth for the best sprints. The thermal performance breadth of T. smaragdinus was broader than that of T. tachydromoides or T. dorsalis, whereas T. dorsalis sprinted faster than the others. In T. smaragdinus, individuals with narrower performance breadths run faster within their thermal range of expertise. There were “specialist” individuals of which performance depended heavily on high temperatures, as well as “generalist” individuals that performed well over a broad range of temperatures even within a single population. We discussed that the spatiotemporal instability of habitats might favor more than one type of thermal reaction norm of sprint performance, and this phenomenon may be driven by specialist–generalist trade-offs.